Our verdict
Pick the Alen BreatheSmart 45i if you want the lower price. Pick the Alen BreatheSmart 75i if your room is larger.
The central trade-off
Rated room size. Alen BreatheSmart 75i: 2,800 sq ft; Alen BreatheSmart 45i: 1,900 sq ft.
Filters. Alen BreatheSmart 45i: HEPA.
Filters. Alen BreatheSmart 75i: HEPA.
Price. When we checked, the Alen BreatheSmart 45i listed for less ($449 against $799); prices move, so check both buttons.
Side by side
| Specification | Alen BreatheSmart 45i | Alen BreatheSmart 75i |
|---|---|---|
| Rated room size | 1,900 sq ft | 2,800 sq ft |
| Smoke CADR | Not stated by the maker | Not stated by the maker |
| CADR | Not stated by the maker | Not stated by the maker |
| Quietest setting | Not stated by the maker | Not stated by the maker |
| Noise | Not stated by the maker | Not stated by the maker |
| Power draw | Not stated by the maker | Not stated by the maker |
| Filters | HEPA | HEPA |
| Warranty | Not stated by the maker | Not stated by the maker |
Values are the makers' published specifications. "Not stated" means the maker doesn't publish it.